In Lambeth, police are investigating the claims and further details are still to emerge. Whatever the outcome of that particular case, many politicians have been quick to use the national debate to make the case for new legislation. Writing in yesterday’s Telegraph, Home Secretary Theresa May said the proposed Modern Slavery Bill will:

Send the clearest possible message. If you are involved in this disgusting trade in human beings, you will be arrested, you will prosecuted and you will be locked up.

The horrors of this case emphasise the crucial need for a new Modern Slavery Bill, along with immediate practical measures to tackle modern slavery, which we are now increasingly aware is taking place through many insidious forms across the country.

The proposed bill has already been widely praised. The Sunday Times, for instance, said it has been described as “the first concerted effort to eradicate slavery since the efforts of William Wilberforce”.

However, Home Office proposals to abolish the “modern day slave trade” in this way will be viewed with some scepticism by migrant domestic workers and their supporters. Those who have entered the UK since 6 April 2012 have been affected by a new visa regime introduced by this government which prevents migrant domestic workers from changing employers or renewing their visa beyond six months.

Live-in domestic workers live and work in a setting that is unmonitored, largely unregulated, and invisible to the outside world. They are heavily dependent on their employer, and this dependency is all the more extreme in the case of migrants who if they leave an employer, however abusive, and work for another person, will find themselves cast as “illegal immigrants”.

Since the new visa was introduced there is evidence that workers’ conditions have markedly worsened. Kalayaan, a support organisation that campaigns for the rights of migrant domestic workers, has found 62% of their clients on the tied visa are paid no salary at all, compared to 14% of clients who entered before April 2012; 96% of tied visa holders are not allowed to leave their employer’s house unsupervised.

End the scourgeIn the langauge of the new bill, “Modern slavery” and “trafficking” are used as interchangeable terms to describe a profitable trade orchestrated by organised criminal gangs.

But what would such a bill have done to address the situation of migrant domestic workers who have, in effect, been taken captive in a private household? It isn’t at all clear.

Neither the police nor the alleged victims have suggested the two individuals who have been arrested in the Lambeth case are members of an organised crime syndicate. Nor has there been anything to suggest that they were interested in accumulating profits.

Police have said that two of the three women allegedly held captive met their alleged captors through a “shared political ideology” before they began living together in a “collective”.

If this were the true, then a bill designed to more severely punish “traffickers” would then be as irrelevant to their case as it is to the vast majority of domestic workers currently on tied visas.

In media and political commentary on trafficking and modern slavery, “traffickers” and other exploiters are frequently described as “preying on the vulnerable”. But “vulnerability” does not simply exist. People become vulnerable when they lack protection, care, access to resources, and social rights.

Will the Modern Slavery Bill address any of these sources of vulnerability? If not, we can only conclude that “anti-slavery” policy is being driven more by the desire to reduce net migration, create a hostile environment for irregular migrants, and punish those who contravene immigration law, than it is by humanitarian concerns.